Sloth refers to extreme laziness or the habit of avoiding work and effort. A person showing sloth doesn't just take reasonable breaks or rest when tired: they consistently choose inactivity over responsibility, letting opportunities and obligations slip away.

The word carries a sense of choosing ease over effort even when action matters. If a student capable of good work demonstrates sloth, they might skip homework not because they're tired but because getting up to find their backpack feels like too much trouble. If someone shows sloth in caring for their pet, they might leave the dog's water bowl empty for too long simply because refilling it requires effort.

Sloth is one of the traditional “seven deadly sins.” It's different from occasionally feeling lazy or needing rest after hard work: sloth means making inactivity a habit and letting it harm yourself and others who depend on you.

The word also names a slow-moving mammal that lives in Central and South American rainforests. These animals hang upside down from tree branches, moving so slowly that algae grows on their fur. Unlike the negative human quality, the animal's slowness is simply how nature designed it to survive. The sloth digests food extremely slowly and conserves energy in an environment where food can be scarce.